The present invention relates to a rocking bed which allows a rest frame (stretcher section) to rock right and left and, more particularly, to a rocking bed for medical use which is capable of rocking at large angles.
A conventional rocking bed, such as shown in FIG. 13, is of an all gear drive type, in which a rest frame 4 supported by struts 2 on a base frame 1 through a rocking shaft 3 can tilt up and down on either side when a worm 12 meshed with a worm wheel 11 that is integrated with the rocking shaft 3 rotates forwardly and reversely.
Further, a first rotating shaft 13 that is integrated with the worm 12 is driven to rotate by an electric motor 20A installed in a driving section 20. The driving force from the motor 20A is transmitted to the shaft 13 through a reducing and reversing mechanism 20B, an output shaft 20a, a gear coupling 21, a first transmission shaft 15, bevel gear shafts 16 and 18, a second rotating shaft 17, and spur gears 14 and 19.
In the above-mentioned rocking bed, the rest frame 4 is rocked by a transmission mechanism that is constructed solely of a gear transmission mechanism. This is advantageous in reducing the cost, but at the same time, it imposes problems that the gears make great noise during operation and that the size of the electric motor as a power source is increased and hence the total cost is elevated.
The present invention has been made to overcome these problems and an object thereof is, therefore, to provide a rocking bed in which a motor is downsized and noise is reduced during the operation of a driving force transmission mechanism, and in which a rest frame for mounting a mattress thereon can rock right and left properly with a simple construction.
To achieve the above object, one aspect of the present invention provides a rocking bed that comprises a base frame, struts respectively erected at both end portions of the base frame, a rest frame for mounting a mattress thereon, which is supported on upper end portions of the struts in a manner rockable right and left, and a driving mechanism for rocking the rest frame, wherein the driving mechanism comprises a motor installed under the rest frame, a reduction gear coupled to a rotating shaft of the motor, an output shaft projecting from the reduction gear in parallel with a rocking axis of the rest frame below the rocking axis, an arm having an upper end portion thereof secured to a distal end of the output shaft to be vertically suspended when the rest frame is in a horizontal position, a vertical guide member provided on the base frame for guiding only vertically a guided member on a lower end portion of the arm, and a motor control section for rotating the motor forwardly and reversely so that forward and reverse rotations of the output shaft allow the rest frame to rock right and left.
Another aspect of the present invention provides a rocking bed, wherein the guided member on the lower end portion of the arm is constructed of an independent roller rotatably supported on the lower end portion of the arm, and the vertical guide member is provided with a pair of guide surfaces for guiding the roller vertically, the guide surfaces closely flanking the roller on both sides of the roller.
Still another aspect of the present invention provides a rocking bed, wherein the guided member on the lower end portion of the arm comprises a roller support member rotatably supported on the lower end portion of the arm and a pair of rollers rotatably supported on the roller support member, and the vertical guide member is constructed as a vertically extending guide bar which is clamped between the pair of rollers.
Still another aspect of the present invention provides a rocking bed, wherein the motor control section comprises a selector switch for inverting the rotation of the motor when the rest frame reaches a preset maximum angle of inclination on the basis of a detected signal from an angle sensor for detecting an angle at which the rest frame is inclined.
Still another aspect of the present invention provides a rocking bed, wherein an inclination angle setting device for adjusting a maximum angle of inclination of the rest frame to a desired angle of inclination is connected to the motor control section.
Even another aspect of the present invention provides a rocking bed, wherein a motor rotating speed setting device for adjusting a cycle for rocking the rest frame right and left is connected to the motor control section.
In the above-mentioned rocking bed, as the output shaft of the reduction gear coupled to the rotating shaft of the motor rotates gently in the driving mechanism that is installed under the rest frame for mounting a mattress, the arm secured to the distal end of the output shaft on its upper end portion at right angles to the output shaft begins to turn, thereby causing the guided member on the lower end portion of the arm to receive a reaction force derived from its abutment with the vertical guide member, and this further causes the arm to gently swing sideward, hence allowing the rest frame to incline quietly while increasing its angle of inclination as the guided member rises along the vertical guide member.
Then, as the motor control section controls the motor to rotate forwardly and reversely, the rest frame begins to rock on either side properly.
Further, when the guided member on the lower end portion of the arm is constructed as the independent roller rotatably supported on the lower end portion of the arm and when the vertical guide member having the pair of guide surfaces closely flanking the roller on both sides of the roller is provided, the lower end portion of the arm can move up and down extremely smoothly, thereby allowing the rest frame for mounting a mattress thereon to rock right and left smoothly as well as quietly.
Still further, when the guided member on the lower end portion of the arm includes the roller support member rotatably supported on the lower end portion of the arm and the pair of rollers rotatably supported on the roller support member, and when the guide bar serving as the vertical guide member is clamped between these rollers, the lower end portion of the arm moves up and down extremely smoothly, and during such movement, the pair of rollers can move vertically while rotating in directions opposite to each other, so that they operate properly in touch with the guide bar without clearance at all times. Thus, the rest frame can rock right and left further smoothly and quietly.
Still further, when the control section of the motor includes the selector switch for inverting the rotation of the motor when the rest frame reaches a preset maximum angle of inclination based on a detected signal from the angle sensor for detecting the angle at which the rest frame is inclined, the forward and reverse driving of the motor can be controlled appropriately at all times and hence excessive inclination of the rest frame can be prevented.
Even further, when the inclination angle setting device, which applies an inclination angle setting signal for adjusting the maximum angle of inclination of the rest frame to a desired angle of inclination, is connected to the control section of the motor, the maximum angle of inclination of the rest frame can be set properly in accordance with the condition of a patient who is lying on the bed, and a maximum angle of inclination of about 60 degrees can even be set, if necessary, after checking that the patient is safely supported on the bed.
When the motor rotating speed setting device for adjusting the cycle of rocking the rest frame on either side is connected to the motor control section, the rocking cycle of the rest frame can be changed easily and smoothly, thereby permitting optimal adjustment of both the maximum angle of inclination of the rest frame and the position of a patient.